Neon matrix circuit for an electronic organ



A ril 4, 1967 w. c. SPENCER 3,31

NEON MATRIX CIRCUIT FOR AN ELECTRONIC ORGAN Filed April 22, 1965 2 Sheets-Sheet l \& Sogxgca +\Oo I v To OTHER DOTENTAL swrrcHis i4 VOLTAGE TO CONTROLLED "AN\PL\ HER KEYER 24 (FOOTAGE TAP) BIAS Aumo PoTENnAL S\GNAL SOURCE souRcE W/u /AM 6. SPENCER INVENTOR /fmz A 7ORNE Y 2 Sheets-Sheet 2 H m C I R C WL/ 00. O N I. N T E u H M H1 N P R 2/ m4 m5 m b W. ww/ ma SQ mlu M a A Jmfix a m v uom wow P u mmfiz W 7 iv Nix Okfi B mv OP 5" In 8 99 N W. C. SPENCER NEON MATRIX CIRCUIT FOR AN ELECTRONIC ORGAN Filed April 22. 1963 M m C9 d1 m5 &

April 4,

- by it becomes conductive.

it biases off the first neon lamp which cannot become.

3,312,768 NEON MATRIX CIRCUIT FOR AN ELECTRONIC ORGAN William C. Spencer, Los Angeles, Calif., assignor, by mesne, assignments, to The Estey Musical Instrument Corporation, Hicksville, N.Y., a corporation of New York Filed Apr. 22, 1963, Ser. No. 275,790 3 Claims. (Cl. 84-4111) This invention relates to switching circuits used in electronic organs and more particularly to improvements therein.

When an electronic organ is played the player depresses the keys, buttons, foot pedals, etc. Actually, these are merely switches which select signals from electrical tone generators. The selected signals arethen applied to voicing circuits the outputs from which are then amplified and applied to one or more loudspeakers to be converted into audible signals. One of the problems arising is that of preventing the operation of the key to select a tone from being injected into the output in a form known as a key click. Also, when keys on the chord keyboard are depressed it is necessary to operate a plurality of keys to select a plurality of tones. Here,

in addition to preventing key clicks a switching arrangement must be provided which simultaneously selects the various tones in response to actuation of the chord key, otherwise the various tones which make up the chord will be heard singly before being combined into the chord. Still another switching problem which occurs in an electronic chord organ is that of blocking out a number of switches and enabling a number of others to be operated in response to playing the keyboard when it is desired United States Patent of blocking out certain switches and enabling others to be operated. v Another object of the present invention is the provision of a novel, useful and simple switching matrix whereby an improved operation of an electronic organ may be etfectuatedr These and, other objects of the invention may be achieved in a matrix employing neon tubes for switching purposes. In place of each key contact used in the organ for switching, there may be provided instead a pair of discharge tubes neon lamps. These have operatingpotentials applied thereto ina manner so that when a key on the keyboard is selected one of these neons is rendered conductive or is illuminated, whereby a voltage controlled keyer may select signals from a suitable audio signal source. In the event that it is desired to prevent signals from this audio signal source from being selected,

a switch applies a potential to the other neon lamp where- Upon becoming conductive conductive despite theactuation of the key whereby it was initially selected.

' The novel features that are considered characteristic of this invent-ion arevset forth with particularity in the appended claims. The invention itself, both as to its organization and method of operation, as Well as addi-' 3,312,763 Patented Apr. 4, 1967 tional objects and advantages thereof, will best be under stood from the following description when read in con nection with the accompanying drawings, in which:

FIGURE 1 is a circuit diagram of an arrangement in accordance with this invention of neon tubes which may be substituted for switch contacts in an electronic organ, and

FIGURE 2 is a circuit arrangement in accordance with this invention of a neon matrix suitable for use in an electronic organ in place of a switching matrix.

Reference is now made to FIGURE 1 which is a circuit diagram illustrating how, in accordance with this invention, two neon lamps may be substituted for two switch contacts. The circuit shown in FIGURE 1 is for only one note key of an electronic organ. Actually, the circuit shown in FIGURE 2 is the one which would be employed with an electronic organ. FIGURE 1 is shown for the purpose of simplifying the description of this invention as it is illustrated in FIGURE 2.

Referring now to FIGURE 1 a source of potential 10, on the order of volts is connected to a bus-bar 12. The note keys on the organ exemplified by the switch 14 may be selectively actuated to connect to the busbar 12.

A resistor 16 serves to connect the key 14 to one end of two neon lamps respectively 18, 20. One of these neon lamps 20, connects to a voltage controlled keyer 22. The other of the neon lamps 18, connects to a switch 24 which is the footage tap of the electronic organ. The voltage controlled keyer 22 is a well known circuit arrangement in the electronic organ field which acts as a gate circuit. In the absence of a potential being applied thereto, signals from an audio signal source 26, cannot pass through the voltage controlled keyer to the amplifier circuits which follow. When a positive voltage is applied to the voltage controlled keyer, it can pass audio signals from the source 26 to the succeeding amplifiers. When the key 14 is closed, the neon lamp 20 is illuminated and becomes conductive and thereby the voltage is applied to the voltage controlled keyer 22 to enable it to pass signals from the audio signal source 26.

The switch 24, whenclosed, connects a negative source of bias potential 28, on the order of minus 50 volts, to the cathode of the neon tube 18. Should the note key 14, also be closed, then the neon tube 18 will fire ahead of the neon tube 20 since it has a higher potential applied thereacross. The current which is drawn through the re sistor 16 drops the voltage at the anode of the neon lamp 20, below the ignition potential value required for the neon lamp 20 to become ignited and therefore neon lamp 20 remains unignited and nonconductive despite the fact that the note key 14 is closed. As a result, the voltage control keyer 22, remains closed and no audio signals are passed from the source 26 therethrough. Therefore, when the footage tap 24 is operated, the neon lamp 20 is prevented from operating.

As briefly indicated above, when playing chords, and also when actuating the various footage keys or taps of an electronic organ, a complex switching problem is presented. It is necessary to inhibit the selection from some audio sources in response to the operation of the note keys and to permit the selection from other audio sources, depending upon which tap switches are closed. Heretofore, this problem has been met in a not too satisfactory fashion, by the employment of multiple leaf contact switches of the type which are usually found in telephone systems. FIGURE 2 shows a circuit diagram of a switching matrix in accordance with this invention in an organ in which there are five footages for example, 2, 4, 5 /3, 8, 12 /5, and 16, and further exemplifying only five note keys which are the octave notes. Thus, the

footage switches have reference numerals respectively 2, 4, /3, 8, 12 /5, and 16, applied thereto and the keys have reference numerals respectively A1, A2, A3, A4, A5. Since there are six footage taps and five octave keys the matrix should contain 30 sets of neon lamps of the type shown in FIGURE 1. However, in order to simplify both FIGURE 2 and the explanation thereof, not all of these will be shown. To do so would complicate the drawingand would only serve to confuse without assisting in a comprehension thereof. A sufficient number of the neon sets will be shown and their interconnections to enable those skilled in the art to understand this invention and to easily duplicate the construction thereof.

One contact of all of the switches A1 through A5 are connected to a common bus which is connected to a source of operating potential on the order of plus 100 volts. One contact of all of the footage switches respectively 2 through 16 are connected to a common bus which is connected to a source of potential on the order of minus 50 volts. The other contact of the switch A1 is connected to one side of the six limiting resistors respectively 16A, 16B, 16C, 16D, 16E, 16F. The other end of each one of these limiting resistors is connected to the anodes of a pair of neon lamps respectively A 18A 203 1813 20C 18C 20D 18D 2013 18E 20F 18F The cathodes of each one of the neon lamps 18A through 18F}, are respectively connected to other contacts of the switches 2, 4, 5 /3, 8, 12 /5 and 16.

The anode of the neon 20A is connected to a voltage controlled keyer circuit 22 and is also connected to the cathode of a neon 2013 and a cathode of another neon 20D The neon associated with the neon lamp 2013 1s designated as 1813 and its anode together with the anode of 20B is connected through a resistor 1613 to the key switch A3. The cathode of the neon 1813;, together with the cathode of the neon 18B is connected to the footage switch 4. 7

.Associated with the neon 20D is the neon 18D;

The anodes of these two neons are connected to the resistor 16D This resistor has its other end connected to the key A5. The cathode of the neon 18D together with the cathode 18D is connected to the footage switch 8.

When none of the footage switches are closed then should the A1 key be closed every one of the neons 20A 20B 2GC 20D 20E 20F,, would be ignited whereby each of the voltage control keyers to which these respective neons are connected will be opened and the audio signal sources 26 to which the voltage controlled keyers are connected, can pass audio signals to the subequent circuits. From the arrangement shown in FIG- URE 2 it will be seen that the neons 20A 20B and 20D all control the same voltage controlled keyer 22 The neon 20B, together with neons 20D and 201 control the voltage controlled keyer 22 The neon 20C controls its own voltage controlled keyer (not shown). The neon 20D together with the neon 20F and the neon ZOF control the voltage controlled keyer 22 The neon 20E controls its own individual voltage controlled keyer (not shown).

Assume now that the footage switch 16 is closed. This causes all the neons 18F through 18F to be ignited. As a result, none of the neons 20F through 20F can be ignited even if the switches A through A are closed Thus, the voltage controlled keyers which are opened by the neons 20F through 20F cannot be fired unless the voltage controlled keyer is controlled in common with a neon on one of the other open footage lines. For example, voltage controlled keyer 22 can still be open by the closing of the A key even though the footage key 16 is closed since the A key can cause the firing of the neon 20D which also controls the voltage controlled keyer 22 From the foregoing description, the operation of the matrix should become apparent. operation of any one of the plies igniting potential to a bus and the neons 29A; through 20F which are connected to that bus are ignited except for those neons associated with an ignited one of the neons 18A through 18F The closure of one of the footage switches 2 through 16 applies an igniting potential to a bus and all the neons 18 which are connected to that line are ignited, whereby they will prevent the ignition of the associated neons 20. Control of the voltage controlled keyer may be achieved by more than one of the neons 20, in accordance with the requirements of the musical scale, the matrix represented in FIGURE 2 exemplifying the switching arrangements required for five octaves of the A chords.

The previous complications in wiring, switch construction and operation, which are replaced by the neon matrix of this invention shown in FIGURE 2, should be apparent. Each one of the neon pairs respectively 18, 20, not only performs the off on and inhibit vfunction but also ties together with other neon pairs to provide alternate control functions when required.

There has accordingly been described and shown herein a novel, usefuhneon matrix arrangement which provides less troublesome operation, better operation and less maintainance than the switching arrangement supplanted thereby.

I claim:

1. In an electronic organ of the type wherein a switching matrix is employed which is operated in response to key switches and footage switches for selectively applying enabling voltages to' a plurality of voltage controlled keyers whereby they can pass signals from a plu rality of audio signals sources to be reproduced, the improvement in said switching matrix comprising a plurality of neon switching circuits, there being as many switching circuits in said plurality as the product of said key switches and footage switches, each said neon switching circuit comprising a resistor, a first and second neon lamp, each having an anode and a cathode, the anodes of said neon lamps being connected to one end of said resistor, means connecting the cathode of said first neon lamp to one of said plurality of voltage controlled keyers, means connecting the other end of said resistor to one of said key switches, means connecting the cathode of said second neon lamp to one of said footage switches, means for providing ignition potential to said first neon lamp when the key switch to which said other'end of said resistor is operated whereby said voltage controlled keyer is enabled to pass audio signals, and means for providing ignition potential to said second neon lamp when said key switch and the footage switch to which the cathode of said second neon lamp is connected is operated whereby said first neon lamp is prevented from being ignited. 2. In an electronic organ of the type wherein the actuator of a key on a keyboard operates a first switch to apply a gating signal to a voltage controlled keyer to enable it to pass signals to be reproduced, the improve ments comprising:

a first and a second discharged tube each having'a first and a second electrode, I a resistor, a first source of voltage potential, means for connecting said resistor, said first switch,

and the first electrodes of said first and second discharge tubes in series with said first source of potential, means connecting the second electrode of said first discharge tube to one of said voltage controlled keyers forenabling said one keyer when said first discharge tube is ignited upon closing of said first switch, a second source of voltage potential, and a second switch for connecting the second electrode of said second discharge tube to said'second source Stated concisely, the. switches A1 through A5 ap- V of voltage potential, said latter potential being selected so that upon closing said first switch when said second switch is closed said second discharge tube will ignite and the voltage drop across the resistor preventing said first discharged tube from igniting.

source of ignition potential connected upon opera- 7 tion of the one of said key switches to said first electrodes of said first and second discharge tubes 3. In an electronic organ of the type having a plurality to ignite said first discharge tube whereby the voltof key switches and a plurality of footage switches, said age controlled keyer is enabled to pass audio signals, key switches and said footage switches being connected and to a matrix for enabling selected ones of a plurality of means including said source of potential responsive to voltage control keyers is, each keyer when enabled pass- 10 the operation of said footage switch to which the ing signals to be reproduced from an audio signal source associated second discharge tube is connected and of in response to operation of selected ones of said key the key switch to which the second discharge tube switches and footage switches, an improved matrix ciris also connected to apply an ignition potential to cuit for selectively operating said voltage controlled said second discharge tube whereby said first diskeyers, comprising: charge tube is prevented from being ignited.

a plurality of discharge control circuits, there being as many discharge control circuits as the product of key switches and footage switches, each of said discharge control circuits containing a first and second dis- Refereuces Cited by the Examiner UNITED STATES PATENTS charge tube, each discharge tube having a first and a 4/1957 Smoot et a1. 317 137 second electmde 2 848 685 8/1958 Mondschein 328 210 means for connecting the second electrode of the first 3061815 10/1962 Tomes 328 104 discharge tube of said each control circuit to at least one of said plurality of said voltage controlled O R REFERENCES keyers, Strassner, R.: Gas-Diode Electronic Organ, Elecmeans connecting the second electrode of the associated second discharge tube to one of said plurality of footage switches,

resistive means connecting the first electrodes of said tronics, vol. 24, #1, January 1951, pp. -74. NEIL C. READ, Primary Examiner. A. J. KASPER, Assistant Examiner.

11/1954 Crosman 340-166 

1. IN AN ELECTRONIC ORGAN OF THE TYPE WHEREIN A SWITCHING MATRIX IS EMPLOYED WHICH IS OPERATED IN RESPONSE TO KEY SWITCHES AND FOOTAGE SWITCHES FOR SELECTIVELY APPLYING ENABLING VOLTAGES TO A PLURALITY OF VOLTAGE CONTROLLED KEYERS WHEREBY THEY CAN PASS SIGNALS FROM A PLURALITY OF AUDIO SIGNALS SOURCES TO BE REPRODUCED, THE IMPROVEMENT IN SAID SWITCHING MATRIX COMPRISING A PLURALITY OF NEON SWITCHING CIRCUITS, THERE BEING AS MANY SWITCHING CIRCUITS IN SAID PLURALITY AS THE PRODUCT OF SAID KEY SWITCHES AND FOOTAGE SWITCHES, EACH SAID NEON SWITCHING CIRCUIT COMPRISING A RESISTOR, A FIRST AND SECOND NEON LAMP, EACH HAVING AN ANODE AND A CATHODE, THE ANODES OF SAID NEON LAMPS BEING CONNECTED TO ONE END OF SAID RESISTOR, MEANS CONNECTING THE CATHODE OF SAID FIRST NEON LAMP TO ONE OF SAID PLURALITY OF VOLTAGE CONTROLLED KEYERS, MEANS CONNECTING THE OTHER END OF SAID RESISTOR TO ONE OF SAID KEY SWITCHES, MEANS CONNECTING THE CATHODE OF SAID SECOND NEON LAMP TO ONE OF SAID FOTTAGE SWITCHES, MEANS FOR PROVIDING IGNITION POTENTIAL TO SAID FIRST NEON LAMP WHEN THE KEY SWITCH TO WHICH SAID OTHER END OF SAID RESISTOR IS OPERATED WHEREBY SAID VOLTAGE CONTROLLED KEYER IS ENABLED TO PASS AUDIO SIGNALS, AND MEANS FOR PROVIDING IGNITION POTENTIAL TO SAID SECOND NEON LAMP WHEN SAID KEY SWITCH AND THE FOOTAGE SWITCH TO WHICH THE CATHODE OF SAID SECOND NEON LAMP IS CONNECTED IS OPERATED WHEREBY SAID FIRST NEON LAMP IS PREVENTED FROM BEING IGNITED. 